1. Field of the Invention
The present invention relates generally to a series fan structure with multistage frame body, and more particularly to a series fan structure having multistage frame body for greatly enhancing vibration absorption effect.
2. Description of the Related Art
Along with the continuous advance of sciences and technologies, the reliance of peoples on various electronic apparatuses has more and more increased. In operation, the internal components of the electronic products (such as computers and laptops) will generate high heat. The heat must be dissipated to outer side of the electronic products in time. Otherwise, the problem of overheating will take place. Therefore, most of the electronic products are provided with fans disposed therein for keeping the electronic products working at an operation temperature within a range.
Please refer to FIGS. 1A and 1B. The fan frames 10 of the current series fan 1 have the same size. The fan frames 10 are assembled with a fan impeller 11, a motor (not shown), etc. to form the fan. In operation, according to the design principle of the motor torque operation, the fan frame 11 will inevitably vibrate. Especially, with respect to a series fan, when the fan impellers 11 inside the fan frames 10 operate and rotate at the same time, under the inter-affection of the vibration frequency of the fan impellers 11, the two fan frames 10 will more severely resonate under resonation effect. The resonation will be directly transmitted outward form the fan frames 10. The hard disc (such as the hard disc in a server) of the mainframe system of an electronic product is especially sensitive to vibration. However, the conventional integrally formed fan frame 10 can hardly reduce the vibration. In some more serious cases, the vibration of the motor and the fan impeller 11 will even interfere with the normal work of other electronic components. This will lead to deterioration of the performance of the system. Moreover, the resonation is always accompanied by loud noise. One of the vibration absorption methods of the conventional fan 1 is to employ vibration absorption fixing structure to achieve the vibration absorption effect. However, such vibration absorption fixing structure includes numerous components and it is complicated to manufacture these components. As a result, the manufacturing cost is relatively high.
According to the above, the conventional device has the following shortcomings:    1. The vibration can be hardly effectively reduced.    2. The vibration will make loud noise.    3. The reading efficiency of the hard disc of the system is lowered.    4. The manufacturing cost is increased.